More evidence that ability to choose delayed gratification (i.e., willpower) is a limited resource. The interesting thing here is the relative activity of the dlPFC. Choosing delayed gratification is associated with activation of a network including the dlPFC, and inactivation is associated with more present-orientation. Demand-avoidance (avoiding tasks which tax willpower) is also associated with low willpower.
Of course the obvious eventual application of this research is to make people behave more rationally by increasing their willpower and therefore the future orientation of the actions they choose. The next step is to understand the mechanism of willpower depletion. Interestingly, in exercise science, there is speculation that what accounts for the latent period between high-impact weight lifting sets is neurotransmitter depletion in the synapse, and restoration on the order of minutes by vesicular transporters. There is also some evidence that neurotransmitter re-uptake inhibitors (specifically SSRIs) can increase the amount of exercise that can be performed until exhaustion (specifically, distance-to-exhaustion in distance runners in my own correspondence). The same thing might be happening in the dlPFC network required for willpower. An initial investigation might be to pharmacologically manipulate neurotransmitter concentration in the synapse in animals models and look at the effect on delay of gratification.
Citation: Kool W, McGuire JT, Wang GJ, Botvinick MM (2013) Neural and Behavioral Evidence for an Intrinsic Cost of Self-Control. PLoS ONE 8(8): e72626. doi:10.1371/journal.pone.0072626
Consciousness and how it got to be that way